宝莲灯 · Cardinal Tetra

Overview

Cardinal tetras, Paracheirodon axelrodi, are traded from both captive production and wild fisheries. Their vivid markings make them conspicuous display fish, but origin matters: wild specimens are less forgiving of declining water quality.

Distribution & habitat

The species occurs in the Negro and Orinoco systems across Brazil, Colombia, and Venezuela. Shaded blackwater creeks characterize many Negro localities. In the Orinoco basin, some populations instead occupy clear, sandy waters with dense vegetation.

Seasonal flooding changes the available shelter. Fish gather around channel leaf deposits during low water, then spread into flooded vegetation and root tangles as water rises.

Aquarium setup

Provide cover with plants or arrange sand and branching wood into a sheltered layout. Floating plants help create subdued light. Leaf litter supplies hiding places and surfaces for microorganisms, which can supplement the diet of fry. Wild fish benefit particularly from soft, acidic conditions and careful upkeep.

Diet & feeding

An omnivorous natural diet is suspected rather than established with certainty. Captive fish accept dry foods, but small live and frozen items should also feature regularly. Water fleas and bloodworms offer useful variety.

Behaviour & compatibility

Keep a mixed-sex group of at least eight to ten individuals. Peaceful schooling companions can encourage confidence. Similar-sized tetras, small catfish, and carefully selected nonpredatory cichlids are possible partners.

Sexual dimorphism

Females approaching reproductive maturity generally become fuller-bodied and slightly larger than males.

Breeding

Prepare a separate aquarium with low light, soft acidic water, and gentle sponge filtration. Fine vegetation, mops, or an egg-protecting mesh can provide a workable spawning arrangement. Condition the adults on small live prey before introducing pairs or a breeding group. Pair spawning often occurs at night; unsuccessful combinations can be changed after a few days.

Adults should be separated from the spawn to prevent egg loss. Eggs typically open after 24–36 hours, followed by another three to four days before the larvae swim. Begin feeding microscopic organisms and move on to microworms or brine shrimp nauplii as growth permits. Early development requires protection from light.

Notes

Negro and Orinoco populations differ subtly in stripe shape and the extent of red pigmentation. Relative to the neon tetra (Paracheirodon innesi), cardinals show more extensive red and a broader blue stripe extending farther back.

Few wild individuals are recorded beyond their first year, but aquarium survival can be substantially longer. That field observation is not an aquarium lifespan limit.